Upscaling as ecological information transfer: a simple framework with application to Arctic ecosystem carbon exchange

Transferring ecological information across scale often involves spatial aggregation, which alters information content and may bias estimates if the scaling process is nonlinear. Here, a potential solution, the preservation of the information content of fine-scale measurements, is highlighted using modeled net ecosystem exchange (NEE) of an Arctic tundra landscape as an example. The variance of aggregated normalized difference vegetation index (NDVI), measured from an airborne platform, decreased linearly with log(scale), resulting in a linear relationship between log(scale) and the scale-wise modeled NEE estimate. Preserving three units of information, the mean, variance and skewness of fine-scale NDVI observations, resulted in upscaled NEE estimates that deviated less than 4% from the fine-scale estimate. Preserving only the mean and variance resulted in nearly 23% NEE bias, and preserving only the mean resulted in larger error and a change in sign from CO₂ sink to source. Compressing NDVI maps by 70–75% using wavelet thresholding with the Haar and Coiflet basis functions resulted in 13% NEE bias across the study domain. Applying unique scale-dependent transfer functions between NDVI and leaf area index (LAI) decreased, but did not remove, bias in modeled flux in a smaller expanse using handheld NDVI observations. Quantifying the parameters of statistical distributions to preserve ecological information reduces bias when upscaling and makes possible spatial data assimilation to further reduce errors in estimates of ecological processes across scale.     

The significance of meandering channel morphology on the diversity and abundance of macroinvertebrates in a lowland river in Japan

• 1. Many rivers and streams across the world have been channelized for various purposes. Channel cross‐sections of meandering rivers are asymmetrical and have cross‐sectional diversity in their physical environment; cross‐sections of a channelized river are typically trapezoidal and have little cross‐sectional diversity, both in physical and ecological conditions. Several programmes to restore stream meanders have been undertaken to improve river ecosystems degraded by channelization. However, the association between diversification in the physical environment due to meander restoration and the macroinvertebrate community structure is poorly known.
• 2. This study of a lowland river in Japan assessed how the cross‐sectional diversity of the physical environment changed with restoration of a meander in a channelized river, and how the macroinvertebrate communities responded to the changes in physical habitat variation. Comparisons were made between the macroinvertebrate communities of a channelized reach, the restored meandering reach, and a natural meandering reach.
• 3. Natural meandering and restored meandering reaches showed higher cross‐sectional diversity in physical variables and total taxon richness across a reach than did the channelized reach. Almost all taxa observed in the natural and restored meandering reaches were concentrated in the shallowest marginal habitats near the banks. Shear velocity increasing with water depth had a negative association with macroinvertebrate density and richness.
• 4. This study demonstrated that the shallow river bed along the inside of bends formed point bars that provided a highly stable substrate, a suitable habitat for macroinvertebrates in a lowland river. It is concluded that meander restoration could be an effective strategy for in‐stream habitat restoration in lowland meandering rivers.

Copyright © 2007 John Wiley & Sons, Ltd.     

Comparison of three types of adhesives in attaching coral transplants to clam shell substrates

• 1. Nubbins from 12 coral species were transplanted onto dead giant clam shells at three sites in a lagoon near Bolinao, north‐western Philippines. Transplants were attached using three types of adhesives: cyanoacrylate glue (SG), epoxy putty (EP) and marine epoxy (ME) and were monitored over five months for detachment, in situ mortality and natural self‐attachment by tissue growth.
• 2. Corals attached with SG showed a significantly higher rate of detachment (logrank test) than those attached with either EP or ME (P<0.001 in each case). Also, those attached with EP showed a higher rate of detachment than corals attached with ME (logrank=6.46, P<0.05).
• 3. ANOVA (P>0.05) and survival analysis (logrank=2.85, P>0.05) showed no among‐adhesives differences in in situ mortality. Among the species used, Porites cylindrica, Pavona frondifera, Heliopora coerulea and Porites rus had the highest survivorship with 82%, 80%, 76% and 73%, respectively, of nubbins alive at the end of the experiment and also displayed the highest cumulative rates of self‐attachment. Species with the lowest survival rates included Acropora muricata and four pocilloporids.
• 4. Although there was no significant difference in the number of self‐attaching transplants among the adhesives, corals transplanted using ME and EP self‐attached earlier than those transplanted using SG (logrank=11.19, P<0.01).
• 5. Results from this study highlight the importance of selecting the appropriate means of attaching corals to substrates and carefully considering species‐specific traits of candidate corals for transplantation.

Copyright © 2008 John Wiley & Sons, Ltd.     

Japanese sardine (Sardinops melanostictus) mortality in relation to the winter mixed layer depth in the Kuroshio Extension region

A drastic population change in Japanese sardine (Sardinops melanostictus) has been noted as being related to winter sea surface temperature (SST) in the Kuroshio Extension region. The former studies suggest two possible explanations. One is that temperature itself affects sardine. The other is that SST represents the environmental change of the Kuroshio Extension region and other causes directly affecting sardine. In this study, we found that sardine mortality from post‐larva to age 1 negatively correlated with the winter mixed layer depth (MLD) in the Kuroshio Extension region from 1979 to 1993. During the period of a deep winter mixed layer (during the early 1980s), sardine mortality was low, whereas mortality was high when the winter mixed layer was shallow (during the late 1980s to early 1990s). By using a lower trophic‐level ecosystem model forced by the observed time series of MLD, SST, light intensity and nutrient data, we found that the estimated spring zooplankton density drastically varies from year to year and has a significant negative correlation with sardine mortality. The inter‐annual variation of spring zooplankton density is caused by the winter MLD variation. During the deep winter mixed layer years, a phytoplankton bloom occurs in spring, whereas during the shallow winter mixed layer years, the bloom occurs in winter. The results of our study suggest that the decline in the Japanese sardine population during the late 1980s to early 1990s was due to an insufficient spring food supply in the Kuroshio Extension region where sardine larvae and juvenile are transported.     

地被植物在南京仙林大学城景观规划中的应用

阐述园林地被植物的概念、生态习性,调查研究南京仙林大学城绿地中常见的多年生草本地被植物,同时对地被植物在景观规划中的配置应用及存在的问题进行探讨。     

35技术在城市森林研究中的应用

总结国内外3s技术在城市森林研究领域应用现状,分析其不足,即遥感学家与植物生态学家缺乏沟通、被动遥感优势尚未挖掘、生态系统服务制图滞后、生态系统管理中忽视信息系统建设,以及景观规划的精确性与客观性有待提高等,在此基础上提出相应改进建议,以期为我国城市森林的3S技术应用和城市森林建设工作提供借鉴。     

从城市生态绿地系统建设探讨园林苗木生产

城市生态绿地系统的建设需应遵循生物多样性保护、地被性植物群落保护、乡土树种保护和自然环境修复的原则。在此原则指导下,对苗木的种类、形态、功能以及引种方面提出不同的要求,并指出苗木生产的发展方向和具体措施。     

溧阳市生物多样性评价

为溧阳市生物多样性的保护与利用提供依据,以溧阳市生物物种资源普查成果报告和溧阳天目湖森林公园植物资源调查报告为本底数据,采用综合指标体系评价方法对溧阳市生物多样性进行评价。结果表明:溧阳市生物多样性的综合评分为75分,其中物种多样性评分为35分,生态系统多样性评分为40分。溧阳市生物多样性评价结果等级为一般。     

抗草甘膦转基因大豆(RRS)在黑土生态系统种植的安全性研究

为明确抗草甘膦转基因大豆(RRS)在黑土生态系统种植的安全性,经过连续3年田间和盆栽试验,分析了抗草甘膦转基因漂移(漂流)可能性.及抗草甘膦转基因大豆(RRS)在黑土区对根际牛态系统微牛物数量,氮代谢和两种土壤酶活性的影响结果表明:在自然条件理花粉漂移几乎足不可能的,但如人为加大虫媒传播(大于10头·m-2),抗草甘瞵基因的漂移概率接近0.05%,漂移距离为0.7 m RRS除对根际真菌数影响不显著外,对根际土壤细菌、放线菌、氨化和硝化细菌均表现降低趋势在大豆不同生育期,RRS除对根际上壤真菌数影响不显著外,对根际士壤细菌,放线菌,氨化和硝化细菌均表现降低趋势;RRS根际士壤细菌多样性指数与均匀度指数均低于亲本RRS-S;氨化强度与RRS-S相比差异不显著,RRS根际土壤硝化强度显著低于亲本RRS-S;RRS降低了过氧化氢酶和脲酶活性.     

应用底栖动物完整性指数评价水源地水库溪流健康状态

及时了解水源地水库入库溪流的水生态健康状态对保障供水安全十分重要。依据2010-2011年对浙江省水源地汤浦水库的环境和底栖动物观测资料建立了底栖动物完整性指数(B-IBI)。根据Shannon-Wiener指数、百分比模式相似性指数(PMA)和多元统计分析结果对参照条件进行量化并确立参照点群。从60个候选参数中筛选出6个核心参数参与构建B-IBI指标体系,采用四分法进行量纲的统一,以参照点群25%分位值作为水生态系统健康与否的阈值,并对小于25%的分位值分布范围进行2等分,确立了水源地汤浦水库入库溪流健康评价标准:B-IBI>25.50,健康;B-IBI 12.75～25.50,亚健康;B-IBI<12.75,差。B-IBI分值与溶氧水平和pH显著正相关(P<0.05)。